Insect growth and reproduction control by 4-imidazolin-2 one



United States Patent 0 INSECT GRGWTH AND REPRODUCTIUN CQNTRQL BY4-iMIDAZOLIN-2 ONE Edward .I. Ayers, Modesto, Califi, assignor to ShellOil Company, New York, N.Y., a corporation of Delaware No Drawing. FiledNov. 17, 1 964, Ser. No. 411,700 3 Claims. (Cl. 167-33) This inventionrelates to a method for controlling the growth and reproductionprocesses of insects, and thereby effecting control of those insects.

it has been found that 4-imidazolin-2-one has a profound and uniqueeffect open the development of insects, for when a developing insect issubjected to it, at one point or another the development is arrested,the insect ceases to develop, and dies. From the available evidence, itappears that 4-imidazoline-2-one interferes with growth processes indeveloping insects which involve differentiation of tissue; it mayinterfere directly with the tissue differentiation, or it may inhibithormones which effect and control tissue differentiation, or both. Itwill be appreciated that the growth processes of insectsthose of allanimals for that matterare extremely complex, and have not beencompletely elucidated, and are not completely understood. It istherefore not possible at this time to say with certainty just whataspect or aspects of the growth process or processes is or are affectedby 4- imidazolin-Z-one. That it does affect the vital processes ofdeveloping insects, and that it does arrest the development of theinsects, has been clearly shown, however, by the experimental Workperformed to date. Thus, it has been founde that when larvae of thecommon housefly (Musca domestica) are fed on media containing aneffective amount of 4-imidazolin-2-one the larvae pass into the pupalstage normally, but no adults emerge from the pupae, the insectapparently dying at some time during its life as a pupa. It also hasbeen found that when an effective amount of 4-imidazolin-2-one ispresent in the food that they eat, the larvae and nymphs of such insectsas the large milkweed bug (Oncopeltus fasciatu s) fail to furtherdevelop normally-they fail to pass from one instar to another (they failto molt) and/or they fail to pupate and/or fail to transform into adultinsects. Mosquito (Anopheles albimanus) larvae failed to advance fromone instar to the next and fourth instar larvae did not pupate, whenplaced in water containing an effective amount of the compound, and evendeath of the larvae occurred in some instances. Further, when adulthouseflies were fed on a medium containing an effective amount of4-imidazolin-2-one the females failed to lay eggs, and when adult (andlast instar) large milkweed bug nymphs were injected with 4-imidazolin-2one they failed to reproduce. The apparent diiference in the'way inwhich this chemical affects the insects is believed to result only fromthe different sequences of growth processes involved in the developmentof the different species of insects. It is believed that in all casesthe chemical is affecting the same kinds of growth process (tissuedifferentiation) and/or are inhibiting the efiect of the same hormone,whether the growth process and/ or hormone effect is taking place in thedevelopment of a viable sperm, a viable action of 4-imidazolin-2-one. Inone subgeneric aspect, the method comprises providing in the food and/or water to be consumed by an insect an amount of 4-imidazolin- 2 -onesufficient to adversely affect developmental growth and reproductiveprocesses of the insect. In another subgeneric aspect, the methodcomprises providing in the food and/or water to be consumed by adultinsects 4- imidazolin-Z-one in an amount sufiicient to sterilize theadult insects. In another subgeneric aspect, the method comprisesproviding in the food and/or water to be consumed by a immature insect4-imidazolin-2-one in an amount SllfllClBIlt to prevent maturation ofsaid immature insect. In yet another subgeneric aspect, the methodcomprises providing in the aquatic medium in which an immature insectdwells an amount of 4-imid azolin-2-one suflicient to prevent maturationof said immature insect. In still another subgeneric aspect, theinvention comprises the method for controlling insects which employ asgrowth mediai.e., which feed upon and/ or dwell in-the excreta ofmammals and birds, which comprises providing in the feed and/or waterconsumed by the animals a dosage of 4-imidazoline-2-one sufficient toprovide in the excreta of the animals an amount of the compoundsuflicient to adversely affect the growth and reproduction processes ofinsects which employ the excreta as growth media, especially to preventmaturation of immature insects feeding upon and/or dwelling in theexcreta.

' 4-imidazolin-2-one is a well-known compound. The manner in which itcan be prepared is given in the literature (JACS, 68: 2350; JACS 54:3414).

From the available evidence, 4-imidazolin-2-one affects the vitalprocesses involved in the development of insects, generally. By insectsis meant not only the members of the class insecta, but also related orsimilar organisms belonging to allied classes of arthropods andincluding mites, ticks, spiders, wood lice, and the like.

4-imidazolin-2-one can be employed for controlling the developmentalgrowth proceses of insects by introducing the compound into the foodand/ or water which the insects consume, and/ or into a medium in whichthe insect is developing. Thus, adult insects can be sterilized byintroducing the compound into their food or water before there hasoccurred in the insects, generation of sperm (in the males) or formationand/ or deposition of viable eggs (in the female). The developmentprocesses of immature insects can be interrupted by introducing a4-imidazolin-Z-one into their food and/or water, or into theirenvironment or medium in which they are developing in the case ofaquatic insect forms, introducing the compound into their aquaticenvironment; in the case of insect forms that develop in excreta frommammals, introducing the compound into the excreta. The compound can beintroduced directly into the food and/or water to be consumed by theinsect, or into the medium in which it is growing, as by spraying,dusting or simply mixing the compound with the food, Water and/ ormedium. In addition, or alternatively, the compound can be introducedinto the medium in which the insect forms are developing, such as theexcreta from mammals and birds, by including the compound in the foodand/or water which the mammals and birds consume.

4-imidazolin-2-one can in many cases be used neat, in the form of powderor dust, which is brought into the insects food. Thus, the compound canbe dusted or sprinkled onto garbage or other refuse, on the droppings oflivestock and other animals, on plants attacked by chewing insects, todisseminate the compound on and/or in the insects food or soliddevelopment media; or the compound can be dusted or sprinkled on ponds,streams and other sources of water which insects consume or in whichthey develop. If desired, the compound can be formulated as dusts orgranules, employing conventional solid carriers and extenders, andincluding adjuvants such as stickers. Alternatively, the compound can bedissolved in water and the resulting solution used instead of thepowdered materials. The liquid formulations of the active material caninclude such adjuvants as the conventional stickers, spreading agents,Wetting agents, and the like. If desired, the active material can bedisseminated in the form of an aerosol, as by dispersing it by means ofa compressed gas.

4-imidazolin-2-one has been found to be essentially nontoxic to mammalsand birds at the dosages required to effectively control thedevelopmental growth processes of insects which feed upon and/or developin excreta from those mammals and birds; furthermore, it is not known tohave any adverse effect upon mammals and birds when used at thosedosages. In addition to effecting control of insects which feed uponand/ or develop in excreta from the mammals and birds this compound alsowill effect control of parasitic insects present in the gastrointestinaltract of the mammals and birds by affecting the developmental growthprocesses of those insects. It apparently is platable to mammals andbirds, and can readily be introduced into the animals in the feed and/or water consumed by them. By introducing the compound into the animalfeed and/or water, it is possible to control both internal parasites ofthe animal and also insects which feed on and/or develop in the animalsdroppings and/or urine, thus providing control of insects such ashouseflies and stable flies without the necessity for spraying theexcreta.

The concentration of 4-imidazolin-2-one in the insect food, water orgrowth medium required to interfere with developmental growth processesof the insect, as might be expected varies from species to species ofthe insects involved. In general, however, a concentration of at leastabout 5 parts of the compound per million parts (by weight) of the food,water or growth medium is necessary, and usually it will be founddesirable to employ somewhat larger concentrations, for example, 50parts per million or more, on the same basis. However, in some caseswhere an adult insect does not consume much food and feeds only forshort periods of time a much larger dosage of the compound may berequired to adversely affect reproduction. In such instances as much as0.1 percent by weight in the food or water of the compound may berequired. In most cases, dosages of from about to about 500 parts permillion will be found effective, yet economical.

When the effective dosage of 4-imidazolin-2-one in an animals feces isto be attained by feeding the compound to the animal, due allowance mustbe made for the fact that some of the compound inevitably is lost in itsPassage through the animal. In the case of the monogastric animals-dogs,cats, mice, horses, pigs and the like-the amount of the compound lostduring passage through the animal is not great, relatively, and ingeneral the dosage of the compound to be fed the animal will be fromabout one and one-half to three times the dosage required in the animalexcreta. In ruminants, considerably more of the compound can beexpected'to be lost in passage through the animalprobably because ofabsorption in the rumen, because of attack by microorganisms in therumen and because of attack by gastric juices throughout thegastrointestinal tract of the animal. If the compound is used neat, itis generally necessary to provide in the animal feed and/or water adosage of from about four to about six times the dosage required in theanimal excreta. Alternatively, the compound may be fed to the animal ina formula in which it is protected from the effects of gastric juice,microorganisms and absorption by the animal. Thus, the compound may bemicroencapsulated, in the form of spansules, impregnated in resins,impregnated in controlled solubility starches, clays and the like, or inthe form of any of the other slow release formulations known to andcommonly used in medical and veterinary practice.

The effects of 4-imidazolin-2-one upon insects are demonstrated by thefollowing experiments and their results.

Example I.-H0useflies TABLE I.-EFFECT OF 4-IMIDAZOLIN-2-ONE ON HOUSEFLYREPRODUCTION Adult mortality, percent;

Sterilant effect, percent Concentration in food, percent/w.

In further housefly tests it was found that when 50 ppm. of 4imidazolin-2-one was added to housefly rearing media, that completeinhibition of larval growth was obtained. When 20 ppm. was added to therearing media only one-third of the larvae completed development.

Example II.C0rn earworm When 0.1% 4-irnidazolin-2-one was added to asugar solution and fed to adult corn earwoprn, Heliothis zea, moths, thenumber of eggs laid by the moths and the number of worms hatchingtherefrom was greatly reduced when compared to untreated controls fedonly sugar water.

Example IIl.Large milkweed bug As little as one microgram of4-imidazolin-2-one injected into fifth instar large milkweed bug nymphsrendered the adults, which developed from the treated individuals,sterile. The compound affected the reproduction of the insect and yetwas not toxic to this species at the effective dosage.

Example I V Mosquito (Anopheles albimanus) larvae grouped by mstar wereplaced in a series of jars containing various parts per million byweight of 4-imidazolin-2-one in water. At 10 p.p.rn. the larvae wereunable to complete their development while at 5 ppm. only 50% of thelarvae completed their development.

Example V Tests were performed to demonstrate whether 4-imidazolin-2-onecould be fed to an animal to control insects which breed and/ or feed inthe excrement of the animal.

Japanese quail were fed 250 parts per million by weight of4-imidazolin-2-one in their ration for for several days. The droppingsof the birds were collected and the droppings from the treated birdswere compared to the droppings of untreated birds as a media forhousefly development. It was found that the droppings from treated birdsproduced 96% less fly maggots than the droppings from untreated quail.The 4-imidazolin-2-one showed no apparent toxic effects upon the birds.

I claim as my invention:

1. A method for controlling insects, which method com prises providing4-imidazolin-2-one in at least one of the food and water to be consumedby an insect, the dosage 5 6 of said compound being nontoxic to theinsect but sufiiwater to be consumed by an animal to control insectscient to adversely affect the development growth and rewhich employ asgrowth media the excreta of the animal. production processes of theinsect and. is an amount up to approximately one-tenth of one percent byweight of References Cited y the Examine! the food and Water. 5 UNITEDSTATES PATENTS 2. A method according to claim 1 wherein 4-imidazolin-Z-one is provided in the aquatic medium in which an immatureinsect is dwelling.

3. A method according to claim 1 wherein a 4-imid- JULIAN LEVITT PrimaryExammer' azolin-Z-one is provided in at least one of the food and I. D.GOLDBERG, Assistant Examiner.

3,136,774 6/ 1964 Stoffel 167-33

1. A METHOD FOR CONTROLLING INSECTS, WHICH METHOD COMPRISES PROVIDING4-IMIDAZOLIN-2-ONE IN AT LEAST ONE OF THE FOOD AND WATER TO BE CONSUMEDBY AN INSECT, THE DOSAGE OF SAID COMPOUND BEING NONTOXIC TO THE INSECTBUT SUFFICIENT TO ADVERSELY AFFECT THE DEVELOPMENT GROWTH ANDREPRODUCTION PROCESSES OF THE INSECT AND IS AN AMOUNT UP TOAPPROXIMATELY ONE-TENTH OF ONE PERCENT BY WEIGHT OF THE FOOD AND WATER.